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Diffstat (limited to 'plugins/FTPFileYM/curl-7.29.0/lib/README.multi_socket')
| -rw-r--r-- | plugins/FTPFileYM/curl-7.29.0/lib/README.multi_socket | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/plugins/FTPFileYM/curl-7.29.0/lib/README.multi_socket b/plugins/FTPFileYM/curl-7.29.0/lib/README.multi_socket new file mode 100644 index 0000000000..d91e1d9f27 --- /dev/null +++ b/plugins/FTPFileYM/curl-7.29.0/lib/README.multi_socket @@ -0,0 +1,53 @@ +Implementation of the curl_multi_socket API + + The main ideas of the new API are simply: + + 1 - The application can use whatever event system it likes as it gets info + from libcurl about what file descriptors libcurl waits for what action + on. (The previous API returns fd_sets which is very select()-centric). + + 2 - When the application discovers action on a single socket, it calls + libcurl and informs that there was action on this particular socket and + libcurl can then act on that socket/transfer only and not care about + any other transfers. (The previous API always had to scan through all + the existing transfers.) + + The idea is that curl_multi_socket_action() calls a given callback with + information about what socket to wait for what action on, and the callback + only gets called if the status of that socket has changed. + + We also added a timer callback that makes libcurl call the application when + the timeout value changes, and you set that with curl_multi_setopt() and the + CURLMOPT_TIMERFUNCTION option. To get this to work, Internally, there's an + added a struct to each easy handle in which we store an "expire time" (if + any). The structs are then "splay sorted" so that we can add and remove + times from the linked list and yet somewhat swiftly figure out both how long + time there is until the next nearest timer expires and which timer (handle) + we should take care of now. Of course, the upside of all this is that we get + a curl_multi_timeout() that should also work with old-style applications + that use curl_multi_perform(). + + We created an internal "socket to easy handles" hash table that given + a socket (file descriptor) return the easy handle that waits for action on + that socket. This hash is made using the already existing hash code + (previously only used for the DNS cache). + + To make libcurl able to report plain sockets in the socket callback, we had + to re-organize the internals of the curl_multi_fdset() etc so that the + conversion from sockets to fd_sets for that function is only done in the + last step before the data is returned. I also had to extend c-ares to get a + function that can return plain sockets, as that library too returned only + fd_sets and that is no longer good enough. The changes done to c-ares are + available in c-ares 1.3.1 and later. + + We have done a test runs with up to 9000 connections (with a single active + one). The curl_multi_socket_action() invoke then takes less than 10 + microseconds in average (using the read-only-1-byte-at-a-time hack). We are + now below the 60 microseconds "per socket action" goal (the extra 50 is the + time libevent needs). + +Documentation + + http://curl.haxx.se/libcurl/c/curl_multi_socket_action.html + http://curl.haxx.se/libcurl/c/curl_multi_timeout.html + http://curl.haxx.se/libcurl/c/curl_multi_setopt.html |